1. Field of the Invention
The present invention relates to an image forming apparatus having an open/close member rotatably supported by a main body of the image forming apparatus to open and close a recording medium conveying path between a transfer device and a fixing device, and more particularly relates to an image forming apparatus having the open/close member provided with a shutter mechanism to cover a surface of the image bearing member when the open/close member is opened.
2. Discussion of the Background
Typically, an image forming apparatus, such as a copying machine, a facsimile, a printer, a multi-functional machine including at least two functions of the above-mentioned products, etc. includes an image bearing member to form a toner image thereupon. Also, a transfer device is positioned adjacent to the image bearing member to transfer the toner image formed on a surface of the image bearing member onto a surface of a recording medium and from a lower part of the image forming apparatus. A cleaning device cleans the surface of the image bearing member by removing remaining toner from the surface of the image bearing member after the toner image has been transferred therefrom onto the recording medium. And, a fixing device is provided in an upper part of the image forming apparatus to fix the toner image transferred from the surface of the image bearing member onto the surface of the recording medium when the recording medium passes through the fixing device.
The image forming apparatus further includes an open/close member rotatably supported by a main body of the image forming apparatus to open and close a recording medium conveying path between the transfer device and the fixing device for removing a recording medium jammed in the recording medium conveying path. A shutter mechanism is provided to protect the surface of the image bearing member which is exposed to the outside of the main body of the image forming apparatus when the open/close member is opened.
FIG. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus having the above-described configuration. The image forming apparatus has an advantage such that the size of the apparatus can be made relatively compact because a recording medium is conveyed through an approximately straight conveying path from a lower part to an upper part of the image forming apparatus, as illustrated in FIG. 1, and thereby the entire recording medium conveying path can be made relatively short. A time period for a recording medium to be conveyed through the entire conveying path can therefore be shortened.
Further, a recording medium jammed in the recording medium conveying path between the transfer device and the fixing device can easily be removed because the recording medium conveying path between the transfer device and the fixing device is exposed to the outside of the main body of the image forming apparatus by opening the open/close member as noted above.
In the above-described image forming apparatus of FIG. 1, when the open/close member is opened, the part of the surface of the image bearing member facing the open/close member is exposed to the outside of the image forming apparatus and receives light from the outside of the image forming apparatus. As a result, when the open/close member remains open for a long time, the image bearing member may be deteriorated by receiving the external light.
In addition, when the open/close member is opened by a user to remove a recording medium which is jammed in the recording medium conveying path between the transfer device and the fixing device, if the exposed part of the surface of the image bearing member is touched by the user's hand or comes into contact with the jammed recording medium, the surface of the image bearing member may be soiled or damaged. If an image is formed on a thus soiled or damaged surface of the image bearing member, the quality of the image will be deteriorated.
Japanese Laid-Open Patent Publication No. 6-186798 describes an example of an image forming apparatus having a shutter to protect the surface of the image bearing member that is exposed when the open/close member is opened.
FIG. 6 is a partial cross-sectional view illustrating a closed state of the open/close member in a background image forming apparatus rotatably supported by a main body of the apparatus to open and close a recording medium conveying path between the transfer device and the fixing device, in which a shutter to cover the surface of the image bearing member is opened. Further, FIG. 7 is a partial cross-sectional view illustrating an open state of the open/close member in the image forming apparatus of FIG. 6.
The shutter 132 is rotatably supported on a pair of pivots 131 and the shutter 132 rotates centered around a pair of pivots 131 in a direction indicated by a partial circle of a dot-and-a-dash line TA, as illustrated in FIG. 6. When the open/close member 23 is opened, the shutter 132 moves to a protecting position to cover the image bearing member and a transfer device 11 is separated from the image bearing member, as illustrated in FIG. 7. When the open/close member 23 is closed, the shutter 132 retreats to a retreating position and the transfer device 11 returns to the position facing the image bearing member such that a toner image on the surface of the image bearing member is transferred onto the surface of a recording medium Pa by a transfer device 11, as illustrated in FIG. 6.
The above-described shutter 132 of the background art requires a relatively large space for the rotation movement thereof, and therefore the image forming apparatus becomes relatively large. If the main body of the image forming apparatus provided with the above-mentioned shutter 132 is formed in a relatively compact size, the devices which are arranged near the image bearing member, such as, for example, the transfer device 11 and the fixing device 14, must be disposed in a relatively narrow space near the shutter 132 and, as a result, the devices may interfere with the shutter 132 when the shutter 132 is rotated. Accordingly, a flexibility for disposing the devices around the shutter 132 may be decreased.
Furthermore, when the open/close member 23 is opened to remove the recording medium Pa jammed in the recording medium conveying path between the transfer device 11 and the fixing device 14, and the shutter 132 then rotates from the retreating position to the protecting position to cover the image bearing member, the jammed recording medium Pa may be sandwiched between the rotating shutter 132 and the image bearing member as illustrated in FIG. 7. If the recording medium Pa is thus sandwiched, the user must remove the jammed recording medium Pa by opening the shutter 132 with the user's hand. As a result, a possibility for the user to touch the surface of the image bearing member with their hand increases, and a removing operation for the jammed recording medium Pa becomes more complex.